Electric burglar alarm



July 8, 1947. MlLLER 2,423,610

ELECTRIC BURGLAR ALARM Filed June 23, 1945 2- Sheets-Sheet 1 INVENTOR Albert F. Mm

' ATTORNEY 1947. A. F. MILLER ELECTRIC BURGLAR ALARM Filed June 25, 1945 2 Sheets-Sheet 2 ELECTRIC MAGNET INVENTOR 7 Albert F. Miller ATTORNEY Patented July 8, 1947 UNITED STATES PATENT OFFICE Claims.

This invention relates to new and useful improvements in an electric burglar alarm.

More particularly the invention proposes a new and improved burglar alarm which is characterized by a top support member and a bottom member for supporting an electrically operated buzzer, or bell or other alarm, and said bottom member being pivotally connected with and freely depending from said top support member. It is proposed to arrange certain contacts on these members which are arranged to control an electric circuit for operating said electric buzzer. With this construction, it is possible to mount the burglar alarm upon a door knob, or other rotative member so that the alarm will operate when the rotative member is turned. It is also possible to connect the bottom member by a string or other connecting member, or elements with a window or other moving part so that when this part is moved the bottom member will be pivoted relative to the top member and set off the alarm.

Still further the invention proposes toassociate a contract control mechanism with the top support member by which the contacts may be latched in contacting positions. This construction makes it possible to have the electrically op erated alarm work continuously until it is turned off, once it is set into operation.

This invention also proposes a modified form in which a cover is used to encase the contact control mechanism, and electric magnetic means is associated with the control mechanism by which it may be adjusted as desired.

Still further the invention proposes a new and improved electric burglar alarm which is exceptionally simple, eflicient in operation and which may be manufactured and sold at a low cost.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.

In the accompanying drawing forming a material part of this disclosure:

Fig. 1 is a sectional view through a door knob which is provided with an electric burglar alarm constructed in accordance with this invention.

2 is a rear View of Fig. 1.

Fig. 3 is a side elevational view of Fig. 1.

Fig. 4 is a fragmentary view similar to Fig. 1 but illustrating the parts in a difierent condition.

Fig. 5 is another view similar to Fig. 1 but illustrating the parts in still another condition.

Fig. 6 is a fragmentary enlarged horizontal sectional view taken on the line 66 of Fig. 5.

Fig. 7 is an enlarged fragmentary View similar to Fig. 5 but disclosing a modified form of this invention.

Fig. 8 is a side elevational View of Fig. 7.

Fig. 9 is a wiring diagram of the embodiment of Figs. '7 and 8.

The new and improved electric burglar alarm, as illustrated in Figs. 1 to 6 inclusive, includes a top support member it] intended to be mounted upon a shaft I I of a door knob I2, or other turnable object. 'The support member ID is provided with a top clamp l3 by which it can easily be attached on the shaft I i. a top section M which is connected at one side by a pivot or hinge 6 with a bottom section ll. A clamp screw [8 releasably connects the sections I4 and I! together.

A bottom member 2!] for supporting an electrically operated buzzer is pivotally connected by a pintle 2! to freely depend with said top support section. it. An electrically operated buzzer 22 is mounted upon the bottom section 29. The electrically operated buzzer 22 includes standard buzzer unit 23 mounted upon a container 24 in which the usual battery cells not illustrated on the drawing, are housed. These battery cells are connected in the circuit which includes the buzzer unit 23. This circuit may be recognized by noting the terminal 25 of the electric buzzer unit 23 which is grounded at the point 26. This point 26 is located upon a plate 21 which is fixedly attached upon the back of the container 24. The electric buzzer unit 23 has its other terminal .28 connected with a lead 29 which connects with one of the terminals of the battery cells, not shown but located within the container 24. The other terminal of said battery cells is connected with a pair of contacts 3| mounted on the top support member Ill and cooperative with a contact 32 upon the bottom member 20.

More particularly, the contact 32 is formed upon the top of plate 27. The contact 32 is engageable with the contacts 3| when the members I0 and 20 pivot relative to each other. There are two ways in which said members may be thus pivoted. One way would be to turn the door knob l2. This will move the top support member ll] angularly as for example, illustrated in Figs. 4 and 5. Another way to obtain the relative angular position of the members l0 and 20, would be to pull the bottom member 20 laterally relative to the top member II]. To facilitate this second way, a pair of studs 33 are mounted upon the sides This clamp It includes tive to each other.

of the container 24. A string 3% is connected with one of the studs 33 and connects with a standard rubber suction cup 35. This suction cup 35 may be mounted upon a window pane, door or other object which swings open, or moves open. In

this way, the suction cup 35 will be moved, and r of the bayonet slot 39. Now the stud 33 may rest.

freely upon the top end of the contact 32, when Howthe members Hi and 26 are in line with each other. Fig. l and noting that if the stud 38 is moved into the long arm of the bayonet slot 33 it will rest on the top of the contact arm 32. With the parts in this condition, the stud 33 will fall down to one side or the other side of the contact 32 when the members Hi and 28 are pivoted rela- This condition is shown in Fig. 5. In this position of the stud 38, the contact 32 will be locked against one of the contacts 3!. If the bottom member 28 were pivoted in the other direction, in relation to the top member 10, the stud 38 would have fallen to the other side of the contact 32 and would have locked the contact 32 against the other contact 3!.

The operation of the device may be understood from the following:

When the stud 38 is in the short arm of the bayonet slot 33, as illustrated in Figs. 1 to 3, the alarm will be sounded when operated as long as the top member it i at an angle to the bottom member 29. This angular relationship may be made by turning the knob 62 so that the parts are as shown in Fig. l. The angular relationship This may be understood by examining V may also be made by pulling the string 34 so as V to cause the bottom member 29 to pivot relative to the top member Hi.

When it is desired that the alarm continue to operate even after the knob 52, or the string 3:3 is released, it is merely necessary that the stud 38 be rested upon the top of the contact 32 when the members It and 26 are aligned with each other as shown in Fig. 1. Now when the members ar angularly moved the stud will fall down the long arm of the bayonet slot 39 and will lock the main contact 32 against one of the contacts 3|.

In Figs. 7 and 8 a modified form of the in.- vention has been disclosed which distinguishes from the prior form in the way that the stud 38 is set into operative or inoperative position. In

, this form of the invention, the top support member I8 i provided with a casin d5 enclosing the stud 38 so that it cannot be manually moved. The casing is formed from casing sections .5 and 47 located on opposite sides of the top support member Ill. An electro-magnet E3 is slidably mounted within an Opening =39 formed in the top support member iii. More specifically, the core of the electro-magnet 68 has slots in this top and bottom ends into which the edge portions of the opening 49 engage, and by which the electro-magnet is slidably mounted. The electro-magnet 48 may assume a position directly over the long arm of the bayonet slot 39, as shown in Fig. '7. The electro-magnet 13 can be shifted towards the right to assume a position over the short arm of the bayonet slot 39. One

terminal of the electro-magnet is grounded at the point 52. A plate 53 is mounted upon the top support member ill, but is insulated from said member by insulating material 54. This plate 53 is connected with the source of the circuit, by a lead 55 which connects with the contact 3 I A handle 56 is provided which has a stem portion 51 of electric conductive material which may be engaged through an opening 58 in the plate 53. The end'of the stem 5? is provided with a threaded portion 59 which may engage a socket 63 which is mounted upon the side of the electromagnet 48. When the handle 56 is pushed inwards and turned slightly the threads 59 will connect with the socket to and the electric circuit will be closed through the electro-magnet, by the current flowing'from the current source lead 55 to'the plate 53, the stem 5? and the socket 63 which is connected with the ground terminal of the coil of the electro-magnet 58. The electromagnet now attracts the stud 33 which moves up to the top of the bayonet slot 33. The electromagnet 48 may be shifted right or left by moving the handle 55, and the stud 38 will be correspondingly shifted. When the stud 38 is in a position as desired, alined with the long or short arm of the bayonet slot, the handle 56 may be disconnected from the electro-magnet 38, which then looses its magnetism because the electric current no longer flows through it.

In other respect this form of the invention is identical to the prior form and like parts may be recognized by the same reference numerals.

The operation of this form of the invention is substantially identical to the prior form, except that the handle 53 is in the nature of a control key. By using this handle 55 it is possible to control the setting of the stud 38. Without the handle 5%.the stud 38 can not be adjusted.

While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not, limit myself to the precise constructions herein disclosed and the right is reserved to all changes and modifications coming within the scope of theinvention as defined in the appended claims.

'I-Iaving thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

1. An electric burglar alarm, comprising a top support member, a bottom member for supporting an electrically operated buzzer pivotally connected with and freely depending from said top support member, a main contact on said bottom member and cooperative with a pair of straddling connected contacts on the other of said members for closing a circuit when said bottom member swings right or left, an electrically operated control circuit for said buzzer including said contacts and mounted on said bottom memher and controlled with said contacts, a stud slidably mounted in a bayonet slot in said top member for resting on said main contact and falling down alongside of said main contact when bottom member pivots for latching said main contact right or left against one of said pair of contacts, said bayonet slot having a, second arm for holding said stud inoperative, a cover enclosing said stud, and electro-magnetic means for moving said stud in said bayonet slot.

2. An electric burglar alarm, comprising a top support member, a bottom member for supporting an electrically operated buzzer pivotally connected with and freely depending from said top support member, a main contact on said bottom member and cooperative with a pair of straddling connected contacts on the other of said members for closing a circuit when said bottom member swings right or left, an electrically operated control circuit for said buzzer including said contacts and mounted on said bottom member and controlled with said contacts, a stud slidably mounted in a bayonet slot in said top member for resting on said main contact and falling down alongside of said main contact when said bottom member pivots for latching said main contact right or left against one of said pair of contacts, said bayonet slot having a second arm for holding said stud inoperative, a cover enclosing said stud, and means for moving said stud in said bayonet slot, including an electromagnet, and a handle detachably connected with said electro-magnet by which its position may be changed.

3. An electric burglar alarm, comprising a top support member, a bottom member for supporting an electrically operated buzzer pivotally connected with and freely depending from said top support member, a main contact on said bottom member and cooperative with a pair of straddling connected contacts on the other of said members for closing a circuit when said bottom member swings right or left, an electrically operated control circuit for said buzzer including said contacts and mounted on said bottom member and controlled with said contacts, a stud slidably mounted in a bayonet slot in said top member for resting on said main contact and falling down alongside of said main contact when said bottom member pivots for latching said main contact right or left against one of said pair of contacts, said bayonet slot having a second arm for holding said stud inoperative, a cover enclosing said stud, and means for moving said stud in said bayonet slot, including an electro-magnet, and a handle detachably connected with said e1ectro-magnet by which its position may be changed, said top member being provided with an opening, and the core of said electro-magnet having slots engaging the edge portions of said open- 1. An electric burglar alarm, comprising a top support member, a bottom member for supporting an electrically operated buzzer pivotally connected with and freely depending from said top support member, a main contact on said bottom member and cooperative with a pair of straddling connected contacts on the other of said members for closing a circuit when said bottom member swings right or left, an electrically operated control circuit for said buzzer including said contacts and mounted on said bottom member and controlled with said contacts, a stud slidably mounted in a bayonet slot in said top member for resting on said main contact and falling down alongside of said main contact when said bottom member pivots for latching said main contact right, or left against one of said pair of contacts, said bayonet slot. having a second arm for holding said stud inoperative, a cover enclosing said stud, and means for moving said stud in said bayonet slot, including an electro-magnet, and a handle detachably connected with said electro-magnet by which its position may be changed, said cover comprising cover sections mounted upon opposite sides of said support member.

5. An electric burglar alarm, comprising a top support member, a bottom member for supporting an electrically operated buzzer pivotally connected with and freely depending from said top support member, a main contact on said bottom member and cooperative with a pair of straddling connected contacts on the other of said members for closing a circuit when said bottom member swings right or left, an electrically operated control circuit for said buzzer including said contacts and mounted on said bottom member and controlled with said contacts, a stud slidably mounted in a bayonet slot in said top member for resting on said main contact and falling down alongside of said main contact when said bottom member pivots for latching said main contact right or left against one of said pair of contacts, said bayonet slot having a second arm for holding said stud inoperative, a cover enclosing said stud, and means for moving said stud in said bayonet slot, including an electro-magnot, and a handle detachably connected with said electro-magnet by which its position may be changed, said top member being provided with an opening, and the core of said electro-magnet having slots engaging the edge portions of said opening, a plate having an opening through which said handle may be manipulated, insulating material for said plate, a lead connecting said plate with the source of said electric circuit and said handle having a stem of electric conductive material for connecting with the high potential side of said electro-magnet.

ALBERT F. MILLER.

REFERENCES CITED The foliowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 775,723 Getto Nov. 22, 1904 1,110,893 Caulkins Sept. 15, 1914 1,534,589 Hausser Apr. 21, 1925 1,305,190 Bobo May 27, 1919 

